The invention relates to a humidity sensor interference-free dehumidification zero returning device and method. The large aperture of a sintered metal oxide humidity element is provided with an internal electrode, the external diameter of the sintered metal oxide humidity element is provided with an external electrode, a small aperture in the left end of the sintered metal oxide humidity element sleeves a dehumidification tube, the dehumidification tube sleeves a flaring V-shaped spiral rod heater, and the sintered metal oxide humidity element, the dehumidification tube, the external electrode, the internal electrode and the flaring V-shaped spiral rod heater form one body. The device and the method have the following advantages: a liquid has loss when flowing along a flaring spiral micro-slot in order to become oil liquid heating, and is uniformly conducted to the dehumidification tube through flaring openings of the flaring spiral micro-tank, and the dehumidification tube carries out omnibearing and dry dehumidification on the humidity of the sintered metal oxide humidity element, the external electrode and the internal electrode, so a meter rapidly and stably recovers to an original state, that is a zero returning state, and prepares next detection; and the dehumidification method well protects electrodes and prolongs the service life of a humidity sensor.